Mating rates and their adaptive value in spiders of the genus Argiope
Mating systems are the product of the integrated evolutionary interests of both sexes and are defined through female and male mating rates. The mating system of the sexually cannibalistic spider Argiope bruennichi is characterised by moderate polyandry facilitated through the killing of males before they can monopolise a female. Males maximise their paternity with a single female or realise the alternative option of inseminating two females. Males opt for the latter strategy if they encounter a related female. Females cryptically favour unrelated males over siblings by modulating the number of stored sperm. Both mechanisms are adaptive because matings between siblings result in severe inbreeding depression. Hence the avoidance of inbreeding may be a significant selective advantage that shaped mating strategies of both sexes, especially since (unlike in most animals) potential mating rates are low even for males. We will combine field observations with genetic analyses in order to evaluate the selective environment, in particular in relation to the odds for inbreeding and for inbreeding avoidance. Using field and laboratory experiments, we will determine to what extent males avoid inbreeding and whether they do so in a context-dependent manner. We expect to find that individual mating rates reflect flexible mating strategies that integrate information about the local environment. Using a non-standard model system that allows us to test the generality of current evolutionary thinking, our project will provide critical insights on the role of genetic compatibility as a factor in sexual selection.
PI: Jutta Schneider
- Duration: 2011-2014
- Sponsor: DFG